问题
多项选择题
压缩机的效率包括（）几种。
A、等温效率；
B、多变效率；
C、机械效率；
D、传动效率。
答案
参考答案：A, C, D
搜题请搜索小程序“爱下问搜题”
压缩机的效率包括（）几种。
A、等温效率；
B、多变效率；
C、机械效率；
D、传动效率。
参考答案：A, C, D
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| My mother used to ask me what the most important part of the body is. Through the years I would 1 at the correct answer. When I was youngerl thought 2 was very important to us as humans, so I said, "My ears, Mum." She said, "No. Many important people are deaf. But I'd like you to 3 thinking about it and I'll ask you again soon." Since making my first attempt (尝试), I had often thought over the question. So this time I told her, "Mum, it must be our eyes." She looked at me and said, "You are 4 fast. Eyes are the windows of our heart, but the answer is not correct because there are many blind people who are very successful." Over the years, mother asked me a couple more times and always her response (答复) to my answers was, "No, but you are getting 5 every year, my child." Then last year, my grandpa died. 6 was heart-broken and was crying sadly. My mum looked at me when it was our 7 to say our final good-bye to Grandpa. She asked me, "Do you know the most important body part yet, my dear?" I got terribly 8 when she was asking me this at that time. I always thought this was a 9 between her and me. She saw the puzzlement (困惑) on my face and told me, "This question is very important. It shows that you have really 10 your life." She went on with tears in her eyes, " My dear, the most important body part is your shoulders.""Is it because they 11 up my head?" I asked. "No, it is because on them a crying friend or loved one can rest his head. I 12 hope that you have enough friends that you will have a shoulder to cry on when you need it," she said. Then and there I understood what the most important body part meant. | ||||
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